Out of Phase
by Janeway1390
Summary: Post Chosen. Dumbledore askes Buffy to become a teacher at Hogwarts and Voldermort is gathering an army of vampires and demons and looking to summon the power of the Hellmouth. That can only lead to one thing. Apocalypse.
1. Propisition

**A/N **This is my first attempt at a BuffyHP crossover. I hope you like it. I don't know as much about HP as I do about Buffy so If I constantlyget names and things mixed up please tell me. Reviews are very helpful so pleasereview!

Spoilers for everything Buffy. Up to Book 5 (OotP). And spoilers up to Destiny for Angel. After that it goes AU._

* * *

_

Buffy wanted to scream, but she couldn't. She couldn't move. The Slayer felt as if her life force, her soul, was being sucked out of her body. She stared into the cold, dead eyes of her attacker. He floated in the air above her in a black cloak, but he had no body or face. There were only eyes and darkness.

"_No one can stop me now!" It bellowed and let out a sinister laugh. "Everything in this dimension and every other will cower before me. And I will rip out their hearts one by one."_

_Buffy was cold. Her blood was ice running through her veins. There was a scream, but it didn't come from her. _

_Flash_

_A young boy was walking down the street, covered in blood. He was clutching a wand and had a lighting shaped scar on his forehead. He cackled then screamed._

"_No one can stop me! Never!"_

_Flash_

_Sunnydale. The Hellmouth was erupting. Flames spewing everywhere. Demons pouring out of it in hordes. Bodies spewed on the concrete. Xander. Willow. Giles. Dawn. Faith. Angel. Spike. There heads turned to her in unison._

"_NO ONE!"_

Buffy screamed and bolted upright in her bed. Sweat was dripping off of her in buckets. "What the hell was that?" she said aloud, though no one else was in the room. She looked at the clock next to the bed. It was three in the morning.

She picked up the phone and dialed. After three rings someone picked up.

"Yeah?"

"Faith, it's me."

"Shit, B, It three in the morning."

"Did you just have a dream?"

"Yeah, but I doubt it wasn't the same kind you had." She heard Faith chuckle then yawn.

"How do you know?"

"Did you ever get pelvic with a guy with a bull whip?"

"No."

"Then we didn't have the same dream. Why? Do you have one of those scary prophetic ones?"

"I'm not sure. I'll talk to Giles. Go back to bed."

Faith hung up without saying goodbye. Buffy would have called her back just to piss her off, but she was still a little shaky from the dream. The Slayer grabbed her robe and walked out of her room. They had defeated The First and closed the Hellmouth three months ago and this was the first prophetic dream she had since they activated all the Slayers.

She hadn't done much Slayer work since they had moved into the new Watcher's Council Headquarters in London. She wasn't sure if she was excited or not that The Powers That Be decided to show her this. Whatever it was it wasn't good and Buffy wasn't looking forward to another apocalypse.

She knocked on Giles' door and he soon came to open it. He looked tired and Buffy had to remind herself that it was very early in the morning.

"Buffy . . .?"

"Giles, we need to talk."

He was about to protest, but he noticed the dark circles under her eyes and the frantic expression she wore. He moved aside and let her enter.

* * *

"And you believe this was a prophecy?"

"Yes. It was vivid. I felt everything that was happening. But Spike was there and he's dead so maybe not."

"Buffy, not everything in your dreams come to pass or are completely accurate, but most of the time the meaning behind them does."

She nodded knowing all to well. She wasn't sure what it meant or even who or what the people she saw in it were. She was about to ask Giles about the cloaked figure and the boy when they heard a load pop.

Buffy turned around and saw an old man with a long white beard standing in front of them. He looked like a costumed wizard from Halloween, pointy hat and all. She instinctively pulled out her stake and took a step toward him.

"Miss Summers that isn't necessary. I'm not a vampire."

"What are you?"

"I'm a wizard. My name is Albus Dumbledore."

"How did you know my name?"

"You're the Slayer and quite famous. Mr. Giles, I presume?" he asked turning to her Watcher. Giles merely nodded.

"What do you want?" Buffy still held her stake, but it was lowered to her side. She was slightly wary of the wizard, but she didn't get the bad guy vibe from him.

"I have a proposition for you."

"I'm listening." She was curious after all. Truth be told she had been slightly bored since they defeated The First. She thought she would love the chance to be a normal girl, but she had seen and been through too much to stop fighting. It was in her blood.

"I'm Headmaster at Hogwarts School of Witchcraft and Wizardry. I would like you to be a Defense Against the Dark Arts Teacher."

"Witchcraft. How come Willow doesn't know about this?" she asked Giles. He shook his head and took off his glasses.

"Your friend is a witch?" Buffy nodded.

"Ah well, beside the matter. What do you think?"

"Me teach? I'm thinking no isn't a strong enough word. Plus I don't know much about witchcraft."

"That's sort of why we need you. You see there is a very powerful dark wizard named Voldermort who is planning some very evil things. Recently he has recruited vampires and demons to do some of his dirty work. We need someone with your skill and experience to help protect and teach our students."

So there was a new Big Bad. It didn't surprise her. She narrowed her eyes and thought about it a moment. "Do I have to decide right now?"

"Of course not. If you'd like I can show you Hogwarts and explain further. I'm afraid I cannot spend too much time here. I am needed back home."

"Okay. I'll go with you, but I'm not promising anything."

Giles started to protest, but she stopped him. "Look if there really is a new Big Bag who's more qualified than me to kick it's ass?"

"Fine, but come back soon."

She nodded and stood up. "Ready."

He pulled out a strange looking object from his robes.

"What's that?"

"It's called a portkey. It will transport you to Hogwarts."

Buffy eyed it warily, but then complied placing her hand on the object. She felt an odd pulling sensation, then she was gone.


	2. Accepting

**A/N **Thank you so much to those who reviewed. Just a note for this chapter and all the others. "Magic" will refer to the HP type of magic and "Magick" will refer to Willow type magic since that's how they spell it in all the Buffy books and stuff. If you're confused now it'll make sense when you're done reading.

**PadfootObsessed329-** Thanks so much for the offer. If I have questions I'll be sure to e-mail you.

**ka-mia2286-** Dawn and the others won't be going to Hogwarts . . .yet. But they will be in the story in later chapters.

Now on to the story. Please review!

* * *

"Whoa," Buffy said as she hit the ground. The pulling suddenly stopped and she felt queasy.

"The trip can be a little unsettling at first."

"Yeah." The Slayer stood up and brushed herself off. She looked up to survey her surroundings and saw a castle towering before her. "Hogwarts?"

"Let me show you around." Dumbledore led her through the school, showing her all the important areas. It had an old world feel. Buffy realized that she hadn't seen any computers or electrical equipment. For a moment she wondered if they'd traveled back in time. They concluded with the courtyard and she stopped to look at him.

"Where exactly are we?"

"The courtyard outside of the dining hall."

"No, I mean city wise. How do you keep this place hidden from normal people?"

He raised his eyebrows slightly. "Oh. You see our world is slightly out of phase with your reality. It undetectable by muggles, though there have been a few incidents were muggles entered our reality."

"Muggles?"

"Non magic users, such as yourself."

She nodded, taking everything in. The school was nice, but she could tell the old wizard was keeping something from her. There was more to this Voldermort guy than he was letting on. She would question him on it later, after she had a chance to talk to Giles and the others. "Is there anything else I need to know?"

"That depends. Are you going to take the position?"

Buffy thought for a moment then nodded. "Sure. What have I got to lose. It's not like I'm really needed back home."

"How's that?"

"Slayer army. There was a fight with The First Evil and we activated all the Slayers. Actually Willow did it."

Dumbledore was shocked. He didn't know such a thing was possible. He was impressed. "Well that's good news. We can send for your things right away."

"Wait a second. If I'm going to do this, I'm going to do it my way," she started and he nodded at her expectantly. "I don't want the other teachers or students getting in the way of my slaying. I can't keep them safe if they get in my way."

"I agree. I actually hoped you would say that because I believe we should keep your identity as Slayer a secret from the rest of the faculty and students."

"Why?" Buffy asked a little suspicious.

"Well the Watcher's Council and the Ministry of Magic are not on good terms. Thousands of years ago they had a fight about the way magic should be used. Wizards believed that the power came from inside oneself and he could use it however he saw fit and used a wand as a tool to use the magic," he pulled a wand out of his robes and showed it her. "The Council, along with Warlocks, believe that the magick comes from the earth, air, and call upon Gods in spells to aid in their bidding. I believe you call it Wicca and it deals in the Occult. Since then the two factions have never come to terms."

Buffy was starting to understand. Willow hadn't always been a witch. That's why she had never heard of Hogwarts or of this other world. She was using power that wasn't necessarily hers. "But I still don't understand why we can't tell everyone I'm a Slayer."

"You see, many in our world only know that the Vampire Slayer exists. They do not know much else about you. But if they knew you were here they might be alarmed. It's safer for everyone if they don't know what's going on."

"Okay. I'll play along. I'd like to go home, get my things, and say goodbye to my friends before we do anything else."

"Alright,"Dumbledore said handing her the portkey. This will transport you to the Council then back to Hogwarts."

"Alright. I'll see you in a couple of days." She smiled at him and he nodded. Then she vanished.

* * *

Buffy checked all of her things to make sure she had everything. She brought three suitcases and her weapons chest. She had already told Dumbledore that she was going to pass on wearing robes because she couldn't fight in them. He agreed, but she wasn't sure if he was happy about it. So much for her fitting in.

She felt bad leaving everyone, especially Dawn. Buffy had given her the option to go, but Dawn didn't want to leave all her new friends. She liked her new life and Buffy was happy about that. To be honest she hoped Dawn would want to stay because Buffy wasn't sure she wanted her sister to learn magic.

They were all gathered in her room, knowing she would be leaving soon. She looked at them and hoped she wouldn't start crying. She'd never been away from her friends for a year and she was desperately going to miss them. "I think I'm ready."

They al lined up to say their goodbyes, starting with Xander. "We're going to miss you, Buff." he said, hugging her.

"Only half as much as I'm going to miss you."

Faith was next. "Make sure you only tell them the good things about me, B." She smirked and surprisingly hugged her too. Faith wasn't known for really showing her emotions, but over the past few months Buffy had noticed a lot of good changes in her sister Slayer.

"Are gonna start crying on me Giles?"

"No," he said giving her a small laugh. "Be careful. We'll continue researching Voldermort and contact you if we learn anything new."

Willow walked up and Buffy noticed tears in her eyes. Buffy didn't know what she was going to do without her best friend.

"I've got a present for you."

Buffy's eyes lit up as she took the package from Willow and opened it. "It's a cell phone? It's _my _cell phone. As far as presents go I've had better. Plus phones don't even work there."

"I know," the witch said rolling her eyes. "It's a magick cell phone. It'll work anywhere and it has free minutes."

"Will, you're my hero."

Now the only person left was Dawn. She wrapped her sister in a tight embrace. "Be good okay? I'll call you all the time. I love you, Dawnie," she let go of her sister and turned to the group. "I love all of you."

She made sure she was touching all of her things, waved goodbye to her friends, and she disappeared once again.


	3. First Lessons

**A/N **Thanks for the reviews everyone! Keep 'em coming.

**Elmo- **There's only one ship in this story that I know will be together and they're both Buffy characters. I'm also an avid H/H shipper, but I'll keep my mind open on D/H and we'll see what happens.

**eagle219406 -** Thanks for the tip. I'll remember that!

* * *

Harry sat at the Gryffindor table in The Great Hall listening to Ron and Hermoine argue about something. He wasn't paying attention to them because his attention was focused on the blond woman sitting next to Professor Dumbledore. She wasn't very old and she wore muggle clothes. 

"Hey Ron," he said nudging his friend to get his attention. "Who's that?"

Ron looked where he was pointing and shrugged. "I'm not sure. I think she's a new teacher. I've only seen her around a few times."

Harry nodded and didn't pursue it further. Ron and Hermoine and been at Hogwarts for a few days and Harry had just arrived. They hadn't really talked much over the summer. He spent most of his days locked in his room at Privet Drive. It had taken him awhile to deal with Sirius' death, but he knew his godfather would want him to move on. The room quieted when Dumbledore stood and cleared his throat. Harry tuned out most of his speech, but started listening when he mentioned a new teacher.

"We also want to welcome our new Defense Against the Dark Arts instructor, Professor Summers."

There was a round of applause and Professor Summers waved shyly. "Do you think she's evil?" Ron whispered next to him.

"Maybe."

"Normally I'd disagree with you two, but the way things have been going for us I'd be cautious of her," Hermoine looked up at the new teacher then back to her friends. "Well we'll find out tomorrow."

* * *

Buffy went over her lesson plans in her head while she watched her class file in. She was less nervous than she thought she'd be. Being a counselor at Sunnydale High had prepared her for working with students. The room quieted and they looked at her expectantly. She knew there was a lot of mystery surrounding her, from both teachers and students, and she figured she'd use it to her advantage. 

"Hey everyone. My name's Professor Summers and welcome to the new Defense Against the Dark Arts class."

"You're American," A boy with red hair stated staring at her. The Slayer nodded and she saw him share a glance with a boy sitting next to him.

"Let's get started. Can anybody tell me what magick is?"

The room erupted in laughter. Buffy was expecting this and she smiled to herself.

"Do you think we're stupid? Of course we know what magic is," said a boy with platinum hair. He reminded her of Spike and she felt a pang. He had died three months ago and part of her was still mourning for him. "What's your name?"

"Draco Malfoy," he stated as if it should mean something to her.

"Well Malfoy, since you know so much about magic can you tell me what a Warlock is?" He shook his head and looked down. "The first thing you all need to do is forget about everything you've been taught about witches and magic. That's the only way you're going to be able to learn anything in my class."

She launched into a speech about magick, witches, and warlocks. Buffy could tell some of the students already knew a little about magick and were able to accept it while others had trouble grasping the concept.

"Professor, if you don't mind me asking, why are we learning this? No one uses that type of magick in this world."

"You never know when this information may be useful. It's better to be prepared."

"Prepared for what?"

"Whatever comes next. In my line of work you learn to expect the unexpected. Now let's move on," The Slayer turned on the slide machine and turned to the first slide. It was a picture of a normal person then she turned to the next slide which showed the same person as a vampire. "This is a vampire. It can take on the guise of a human until it needs to feed."

She didn't want to overwhelm them on the first day so she stayed to the need to know facts about vampires. Many of the students looked scared when she was finished and that was a good thing. "If you ever see a vampire or any other supernatural being don't try to fight it. Run and get me right away. And whatever you do, never invite them in."

* * *

"I think she's evil." 

"Though it pains me to agree with you, I think you may be right."

"Hermoine, you agree with _me_?" Ron was stunned. That had to be a first. "What do you think Harry?"

"I don't know. I kind of liked her." Harry was actually quite puzzled by her. She didn't act like the other Professors. That was probably because she was American. All he knew was she was very powerful. He could feel it. If she was evil then they were in trouble, but he had a feeling that she was on their side. "I don't think she's evil."

"Well how do you explain that whole 'You need to be prepared' comment? Or the 'In my line of work you expect the unexpected? What's there to expect in teaching? I think she's hiding something."

"You worry too much," Harry said, but he couldn't help but think about what Hermoine said. They would have to keep a close eye on her.

* * *

It was one o'clock by the time Buffy went out to patrol. She had to make sure that everyone was asleep, plus she was working on next class's lesson plans. She wanted to try and call Dawn and the rest of the Scoobies, but she figured it was too late. Well at least she thought it was, Buffy didn't know if there was some weird time difference in this reality. 

The Slayer was walking down a hall on her way outside when she heard footsteps behind her. They were heavy so she figured it wasn't a student. She pretended that she wasn't being followed until she reached an opening. Buffy spun and grabbed her attacker by the arm.

"Snape," she quickly let go of his arm and hid her axe behind her back.

"Professor Summers. What are you doing out so late?"

"Just taking a walk. I don't sleep well. What about you?"

He narrowed his eyes and looked around. "Just patrolling the grounds. Students have a tendency to sneak out of their dorms. This is a difficult time with You Know Who out. You can't be too careful."

"Gotcha. Well I'm just going to be on my way." She backed away from him slowly then started running when she was out of view. That guy gave her the creeps. There were a lot of things in this place that gave her the creeps.

* * *

Harry sat at the window of his dorm room. Lately he was having trouble sleeping. He kept having nightmares of the night Sirius died. Sometimes he had dreams of Voldermort and other things he didn't recognize. He was about to go back to bed when something caught his eye. 

"Ron! Wake up. Come here."

He heard his friend moan then get up and join him at the window. "What is it mate?"

Harry pointed. Ron gasped. They saw Professor Summers emerge from The Forbidden Forrest, covered in blood and dirt. She carried an axe, which was also covered in blood.

Ron gulped and Harry said, "Maybe she is evil."


	4. It's Started

It had been two weeks since Buffy started teaching at Hogwarts and so far there had been no signs of vampires or demons that she recognized. She had killed a few creatures in the Forbidden Forrest, but that was it. Dumbledore had told her that Voldermort was continuing to gather forces. The Slayer knew from experience that the lull in action only meant that the enemy was planning something.

At least her classes were going well. Most of the students liked her and with the exception of some Slytherins, she liked them too. There were three she wasn't sure of though. Harry, Ron, and Hermoine had been wary of her. They acted like they knew something that the others didn't.

It was late and probably past dinner time. Normally she passed on eating with the others. The other Professors hadn't really accepted her and Buffy missed her friends. They had rarely spent much time apart and she forgot how much she relied on them. Most of the time she ate dinner in her office by herself, but it sounded like tonight she would have company when she heard a soft knock at the door.

"Come in."

"Professor Summers, can I speak to you a moment?"

"Sure Harry. What's on your mind?" Buffy let go of the stake she was holding in case her visitor was someone she wasn't expecting. Well she wasn't expecting Harry, but it was better then a vampire.

"Well . . .I uh," he faltered and she looked at him expectantly. "Never mind. Sorry to bother you."

"Are you sure? You can tell me an-" Her sentence was interrupted when Ron and Hermoine burst into her office.

"Do you remember when you told us to come get you when we saw vampires?"

"Yes."

"We saw vampires. They were by the courtyard."

Buffy jumped out of her seat and hurried to her weapons chest. She drew out a sword and put a stake in her jacket pocket. "You three go to you're dorms and stay there."

The Slayer ran as fast as she could to the courtyard. She saw a figure come around a corner and she raided her sword. It was Snape.

"Professor, what are you doing?" She punched him in the face and heard his body hit the ground while she continued to run. She didn't have time for him.

Ron and Hermoine were right. There were three vampires that she could see and one that was hidden by a mob of teachers holding it at wand point. The first vampire charged her. Buffy ducked and punched him in the stomach then launched in a spinning kick to his head. Before he realized what happened his head fell to the ground and he was dust.

The Slayer moved on to the next one. This time he went straight for her sword, kicking it out of her hands. She went to punch him in the face, but he blocked it and punched her instead. Buffy kicked him in the shin, grabbed his arm and spun him around, then implanted the stake in his chest.

The sword was only a few feet away so she ran to it and looked up to find her next attacker, but the third vampire was running away to The Forbidden Forrest. "Wimp."

"Professor Summers, over here!"

The shout came from one of the professors holding off the last vamp. Buffy heard shouting and saw a flash of platinum blond hair. She narrowed her eyes and charged toward them.

"Bloody hell. Stop pointin' those things at me. I'm not gonna hurt you."

That was a voice she knew very well, but she knew it couldn't be him. Despite herself she pushed the witches and wizards aside and found herself staring into his deep blue eyes.

She opened her mouth to say something, but no words came out. Then realization dawned on her and her face fell. The First. Buffy should have known that Voldermort and the First would be together. Without thinking the Slayer raised her fist and connected with the flesh on Spike's cheek.

"Spike? It's really you?"

Before he could answer her arms were around him and she was crying in his shoulder. "I-I thought you were . . .how?"

Spike felt his own eyes get teary and he held her tighter. Neither of them were sure how long they stayed like that, but they both realized there were five wizards staring at them. "Professor do you know him?"

"Yes."

"You do know he's a vampire, right?" Buffy nodded again and took Spike by the hand and led him into the castle.

* * *

"How long were you a ghost?"

"Couple months I guess."

Spike had told her how the amulet brought him back as a ghost and he spent time at Wolfram and Hart waiting for them to make him corporeal again. After he did he had a fight with Angel, then he came looking for her. At least that was all he had told her.

"How'd you know where I was?"

"I called the Council and talked to Willow. She told me that you came here and about the situation. Heard a couple vamps talking about killing a Slayer at Hogwarts. I followed them and here I am."

"Did you hear them say anything else?"

"Not really. I think something about a guy named Voldermort was mentioned. Why?"

Buffy thought for a moment. If Spike was trailing Voldermort's guys then that meant that they knew she was the Slayer, they knew where she was, and that it had started. "New Big Bad. He's actually a very powerful Wizard. You do know about the whole Warlock/Wizard, magick/magic thing right?"

He chuckled and looked like he was recalling something from his past. "About twenty years after I became a vampire I got into a tussle with a few Wizards. That's how I could get into the Wizarding World. I've been here before."

She nodded, thankful that she wouldn't have to explain everything. Buffy couldn't describe how happy it made her to have Spike back. She was really lonely and having someone she loved with her was what she needed. Plus it would be nice to have another fighter if there was going to be another big battle.

"We need to go talk to Dumbledore. I'll explain on the way." She took his hand and led him through the corridors of Hogwarts. Avoiding glances from Professors. Buffy figured the Professors who witnessed her had already or still were complaining to Dumbledore. The Slayer was surprised to see only Dumbledore when she walked into his office.

"Ah Miss Summers. I heard about what happened earlier this evening." He looked to Spike expectantly and Spike looked to her.

"Oh, uh, this is Spike. He's a vampire, but he's good. He has a soul."

The old Wizard nodded accepting her explanation. He motioned for them to sit down and they did. The three sat in silence waiting for someone to speak and it was Buffy who finally did.

"Look I'm sorry about punching Snape. He was in my way."

"It's understandable Miss Summers. And I'm not mad. You did exactly what I needed you to come here and do. The problem now is that we have five Professors who now know more about you than I would like and we have vampires on the grounds and more could be on the way."

"Do you think we should tell them I'm a Slayer?"

He shook his head. "That would only cause panic, but for the safety of the students I think we should call them to meet in the Great Hall and set a few rules as well as explain about our new visitor."

* * *

Everyone was gathered in the Great Hall waiting for the Headmaster to speak. Spike was sitting next to Buffy at the Professor's table behind the podium where Dumbledore stood. He cleared his throat and the crowd quieted. "As some of you may know there was an attack on Hogwarts this evening. I believe Lord Voldermort was behind it," at the sound of Voldermort's name people gasped and averted their eyes. "As a precaution no student is allowed out of their dorms at night. Your House will be escorted to supper by a Professor. If you are out af-"

Dumbledore was interrupted by the load sound of doors slamming open and screams. Buffy was up immediately, running toward the vampires. She jumped on top the Gryffindor table and ran along it, spearing a vampire to the ground when she reached the end. Spike was next to her punching another vampire. They worked as a team just like they had in Sunnydale. They dusted four and were working on the fifth when Buffy turned and saw a vampire standing over Harry saying something to him. The vampire was about to sink his teeth into Harry's neck when Buffy flung her stake at the vampire. The vampire turned to dust. She realized Spike had killed the other one and there were none left. She looked up to see the wide eyed, shocked faces of everyone in the Great Hall.


End file.
